After 15 games of showing steady improvement, No. 16 was a turn for the worse for the Missouri Tigers.

"We took a big step back," Missouri coach Mike Anderson said Monday about Saturday's 89-76 loss at Colorado to open Big 12 Conference play. "We are still a work in progress."

And that work will be concentrated on the defensive end as the Tigers (14-2, 0-1) prepare for Wednesday night's game against the Nebraska Cornhuskers (13-2, 1-0) at Mizzou Arena.

"We are going to work on correcting some things," Anderson said, hinting the Tigers will be putting some extra time on the practice floor.

Anderson wasn't happy with the Tigers' focus in Saturday's game.

"We showed up with the mindset of playing offense and not defense," he said.

And in Anderson's system, that's a no-no.

"We were fighting an uphill battle the whole game," Anderson said. "Colorado had something to do with it, but our defense wasn't what it should have been."

The Buffaloes beat the Tigers at their own game, breaking Missouri's press on repeated occasions to post a pair of 15-2 runs in the opening 20 minutes on their way to a 12-point halftime lead.

"We came out a little flat," Anderson said.

Colorado pushed that advantage to as many as 18 before Missouri cut it to seven with two minutes left. But the Tigers could get no closer.

"We had some opportunities, but we didn't take advantage of them," Anderson said.

Missouri, which entered the game ranked No. 9 in the Associated Press poll, fell to No. 15 in the rankings released Monday. Saturday's win was Colorado's first over a top-10 team since the 2002-2003 season and its first over Missouri in nearly five years.

"No matter who you play, if you don't show up, you can get an "L' pretty quick," Anderson said.

Nebraska is coming off a 63-62 home win over Iowa State on Saturday night. The Cornhuskers will bring at 11-game winning streak into Wednesday's 6 p.m. contest.